We have continued to extend our new technique for measuring IgG Fc receptors in patients with autoimmune disease. These techniques have proven useful in diagnostic tests and for developing an understanding of pathophysiologic processes. Patients with mixed IgM, IgG cryoglobulins can be divided into two groups. The patients with normal Rc receptor function do not appear to develop immune complex mediated renal disease. The follow-up studies have performed in our patients with lupus erythematosus. As the patients improve the immune clearance, defect also improves. Patients with mixed connective tissue disease have been studied and have been shown in general to be free of defects in immune clearance not withstanding the fact that they have circulating immune complexes. Current studies demonstrate an Fc receptor defect in patients with Dermatitis Herpetiformis. Because these patients are all HLA B8 Dw27 we have extended our studies to normal HLA B8 Dw27 individuals. 50% of these have an Fc defect suggesting that this may be one cause of autoimmune disease.